I see. Maybe there should be a separate function
efficientConstrEq :: Constr - Constr - Bool
so that people don't get confused with the standard Eq definition? How
often is the efficient version needed?
In any case, it seems like we should document the fact that the Constr
Eq instance doesn't
These don't seem to have Data instances in 6.4.1:
Language.Haskell.TH.Exp
Data.Tree.Tree
I guess there are probably a lot more, I just ran into these today. Is
there anything which prevents proper 'deriving' clauses from being
added to their definitions?
Frederik
Simon PJ,
Is that Ok?
Should I?
Ralf
-Original Message-
From: [EMAIL PROTECTED]
[mailto:glasgow-haskell-
[EMAIL PROTECTED] On Behalf Of Frederik Eaton
Sent: Thursday, December 29, 2005 11:39 AM
To: glasgow-haskell-bugs@haskell.org
Subject: missing Data instances
These don't
Einar Karttunen wrote:
On 22.12 14:43, Christian Maeder wrote:
How can I detect this sharing in order to avoid traversing the very
same symbol table for every symbol?
By using System.Mem.StableName
SerTH (http://cs.helsinki.fi/u/ekarttun/SerTH/) implements this,
so you can look at the source
Ashley
I think Lennart answered your question rather well. As he says, the
restriction is that an unboxed type must not instantiate a polymorphic
type variable (and that polymorphic type variables may not have an
unboxed kind). You may like to read the paper Unboxed types as
first-class
Tomasz
Intriguing! I'm afraid it'll be some time before your code works,
though.
First I have to get GADTs and type classes to play together nicely,
which I am hoping to do during Jan/Feb. Then I'll have to think about
the interaction between GADTs and fundeps.
As of today, if it works at
| My current uses of GADTs belong to the company I work for, so it would
| be easier for me if *I* could check from time to time. Is the code
| publicly available?
Not yet, I'm afraid. But it will be soon.
Simon
___
Haskell mailing list
On Thu, Dec 29, 2005 at 09:48:04AM -, Simon Peyton-Jones wrote:
Intriguing! I'm afraid it'll be some time before your code works,
though.
No problem, I can wait.
First I have to get GADTs and type classes to play together nicely,
which I am hoping to do during Jan/Feb. Then I'll have
Hello Tomasz,
Unfortunatelly I have only seen your message after Simon answered to it.
I am sorry for the late answer!
| If there is another way to do this right now (conveniently, Oleg! ;-),
I
| would be more than happy to hear about it.
|
| If this worked, it would be a cool trick and a nice
On Thu, Dec 29, 2005 at 12:39:01PM +, Bruno Oliveira wrote:
A second alternative would be to simulate your GADT with a type class and
your constructors with the functions of that type class:
[...]
As a remark, this is a church encoding of the GADT.
[...]
Now you can encode
Hi there, I'm having some trouble trying to get information out
of a HashTable.
I'm using it to represent a set (I'm using a hash table for O(1)
speed reasons to compare against Data.Sets O(lgN) operations).
I'm trying to write a simple function, member, which returns whether
or not a key is in
Hunter Kelly wrote:
How can I get at the underlying value? Can I only access it from
within a do construct?
Yes, I'm afraid so
Is there anyway to get at this function to return just True or False?
No, (unless you use something unsafe that I would not recommend)
Or has using something
On Dec 29, 2005, at 9:06 AM, Hunter Kelly wrote:
Hi there, I'm having some trouble trying to get information out
of a HashTable.
I'm using it to represent a set (I'm using a hash table for O(1)
speed reasons to compare against Data.Sets O(lgN) operations).
I'm trying to write a simple
Hello,
I'm pleased to announce the first release of HDBC-MissingH, a library
to add database features to MissingH.
At the present time, this allows any HDBC database to act as a backend
for the MissingH.AnyDBM architecture. As such, you can use a SQL
database as storage for a simple DBM-like
I agree with the suggestions of the other posters. Sometimes I'll also use
error data to print to get a one time breakpoint :-)
cheers
Hunter Kelly [EMAIL PROTECTED] wrote in message
news:[EMAIL PROTECTED]
Yes, thank you, that did the trick! It produced the output for all steps,
and in the
In article
[EMAIL PROTECTED]
ft.com,
Simon Peyton-Jones [EMAIL PROTECTED] wrote:
The .NET CLR lifts the restriction by specialising code, so that it can
adapt to whether it is moving Int# or Double# values around. In
Haskell, though, it's not possible to statically generate all the
| Using Haskell for this networking app forced me to focus on all the
| issues _but_ the business logic. Type constraints, binary IO and
| serialization, minimizing memory use and fighting laziness, timers,
| tweaking concurrency and setting up message channels, you name it.
That's a
Hello,
On Tue, 27 Dec 2005 16:39:34 +, Chris Kuklewicz wrote:
Happy Holidays,
I was wondering if it this small snippet of code could be altered to
require fewer OPTIONS -fallow-... switches.
Here is a partial solution using only -fglasgow-exts:
module MyShow where
class MyShow t where
I did look into this a little. There are several things going on
* GHC doesn't really expect you to use INLINE and SPECIALISE together.
INLINE says to inline a copy of the function at every call site, which
is the best possible form of specialisation, so SPECIALISE is a bit
redundant if you are
Michael Benfield wrote:
I see here:
http://www.haskell.org/HOpenGL/newAPI/
OpenAL bindings listed as part of the Hierachical Libraries. And when I
download the source to a development snapshot of GHC, there they are. Is
there a way to install this on GHC 6.4?
Alternatively... I can't get
Hello David,
Thursday, December 29, 2005, 3:42:05 AM, you wrote:
stats elems = foldl add_elem Map.empty elems
DR This program has a space leak and runs out of stack space. I'm guessing
DR that I'm being bit here by an unnatural amount of laziness in
DR Map.insertWith
stack overflows AFAIK is
On Thu, Dec 29, 2005 at 11:22:11AM +0300, Bulat Ziganshin wrote:
stack overflows AFAIK is never occur because of laziness, but only
because your recursion is not tail-optimized.
AFAIK, evaluating a thunk in GHC-compiled code does use the stack -
update frames are being put on it.
There is a
Hello,
I haven't followed everything that's happened on the Binary IO
thread, but has anybody else actually tried Joels code? ..
http://wagerlabs.com/timeleak.tgz
I can reproduce the problem (ghc/Linux), but can't explain it. It
seems very strange that friggin about with an otherwise
Thanks for looking, Adrian,
It'd be great if someone was able to find out more about what's going on
here. Bandwidth at GHC HQ is always tight, so the more precisely
someone can pinpoint what's happening, the faster we can fix it. Joel
has done a lot by making a repro case. Maybe others can
Adrian,
There's no mistery here.
Threads take a while to unpickle the large server info packet when
the gang up on it all together. By adding the MVar you are basically
installing a door in front of the packet and only letting one thread
come through.
The end result is that you are
David Roundy wrote:
stats elems = foldl add_elem Map.empty elems
add_elem m x = Map.insertWith (+) x 1 m
main = print $ stats $ take 100 $ repeat 1
This program has a space leak and runs out of stack space. I'm guessing
that I'm being bit here by an unnatural amount of laziness in
On Thu, Dec 29, 2005 at 01:02:45PM +, Adrian Hey wrote:
I haven't followed everything that's happened on the Binary IO
thread, but has anybody else actually tried Joels code? ..
http://wagerlabs.com/timeleak.tgz
I have and I am puzzled too.
I can reproduce the problem (ghc/Linux), but
On Thu, Dec 29, 2005 at 01:20:41PM +, Joel Reymont wrote:
Why does it take a fraction of a second for 1 thread to unpickle and
several seconds per thread for several threads to do it at the same
time? I think this is where the mistery lies.
Have you considered any of this:
- too big
On Thu, Dec 29, 2005 at 01:42:29PM +0100, Christian Maeder wrote:
David Roundy wrote:
stats elems = foldl add_elem Map.empty elems
add_elem m x = Map.insertWith (+) x 1 m
main = print $ stats $ take 100 $ repeat 1
This program has a space leak and runs out of stack space. I'm
Bulat Ziganshin writes:
your BlockIO library is great, but it's usage is limited
to very specific sutuations - when we can save pass state
between processing of individual bytes
In my experience, any other approach to I/O is slow. If you
don't have an explicit state between processing of
On Thu, Dec 29, 2005 at 04:24:02PM +0100, Jean-Philippe Bernardy wrote:
On 12/29/05, David Roundy [EMAIL PROTECTED] wrote:
On Thu, Dec 29, 2005 at 01:42:29PM +0100, Christian Maeder wrote:
David Roundy wrote:
stats elems = foldl add_elem Map.empty elems
add_elem m x = Map.insertWith
Hi,
I am trying to read _Arrows, Robots, and Functional Reactive
Programming_ by Hudak, et al.
http://www.haskell.org/yampa/AFPLectureNotes.pdf
In section 2.1 there are a number of equations of the form:
g’ :: SF A C
g’ = arr g
= arr f1 arr f2
and
i’ :: SF (A,C) (B,D)
i’ = arr i
On Dec 29, 2005, at 11:26 AM, David F. Place wrote:
Hi,
I am trying to read _Arrows, Robots, and Functional Reactive
Programming_ by Hudak, et al.
http://www.haskell.org/yampa/AFPLectureNotes.pdf
In section 2.1 there are a number of equations of the form:
g’ :: SF A C
g’ = arr g
=
On Thu, Dec 29, 2005 at 03:34:10PM -0500, Cale Gibbard wrote:
The issue with it taking too long seems to basically be as Joel said,
only one of the threads can take that MVar at a time. Even if the time
that it's taken is fairly short, if one is running faster than the
others, it tries to take
Albert Lai writes:
For almost a decade, most (I dare claim even all) Pascal
and C compilers were three-pass or two-pass. It means
perhaps the compiler reads the input two or three times
[...], or perhaps the compiler reads the input once,
produces an intermediate form and saves it to
On Thu, 2005-12-29 at 15:56 -0500, Albert Lai wrote:
. . .
one-pass fast method, since for almost a decade no one did it. Most
of us had to wait until someone figured it out and then we had Turbo
Judging from comments by U. Ammann [1],[2], part of the original Pascal
implementation team at
Laziness and strictness are both important depending on the situation.
I'd recommend keeping both variants around. Having to wrap values in
an extra data type just to keep laziness sort of defeats the point of
Haskell being lazy in the first place. It also makes it somewhat
awkward to use in the
Also, if you are trying to display a line that looks like
insert 5
or
consume 6
then consider using
putStrLn (insert ++ show r)
putStrLn (consume ++ show r)
instead of
print (insert ++ show r)
print
I particularly like OCaml's provision of subtyping. As a member of
the ML family, it's module system is also quite formidable. Of course
the imperative constructs are also pretty convenient when you just
want to be quirky. But I miss the monad do-notation.
Here's a version that provides clean output with no delays. It uses a
single-entry mailbox (the TMVar output) to ensure the processing
doesn't run too far ahead of the log.
module Test where
import System.Random
import Control.Concurrent
import Control.Concurrent.STM
test :: IO ()
test =
do
On Dec 23, 2005, at 11:53, Arjen wrote:
On Fri, 23 Dec 2005, Joel Reymont wrote:
Folks,
I have been looking at the code for the Arrows for invertible
programming paper (http://www.cs.ru.nl/A.vanWeelden/bi-arrows/) and
I have a question about syntax. ghci surely does not like it.
I've
On Fri, Dec 16, 2005 at 07:55:50AM -0800, Scherrer, Chad wrote:
From: S Koray Can [mailto:[EMAIL PROTECTED]
Why not do this: name none of those modules Main.hs, and have an empty
module Main.hs with only import MainDeJour and main =
MainDeJour.main so you can just edit just that file.
From: Isaac Gouy [EMAIL PROTECTED]
To: haskell-cafe@haskell.org
Subject: [Haskell-cafe] Re: Haskell Speed
Date: Thu, 29 Dec 2005 13:00:15 -0800 (PST)
--- Isaac Gouy [EMAIL PROTECTED] wrote:
We'll be happy to also show a Haskell program that
uses Data.HashTable - first, someone needs to
On Dec 29, 2005, at 7:44 PM, Branimir Maksimovic wrote:
To comment some observation on this program.
Most of the pressure now is on Data.HashTable.
I've susspected such large memory usage on substring from array
conversions,
so mad version with data MyString = MakeMyStrinf { buf :: Ptr Char,
Yes, good point. I suppose there's really no need to re-declare main once it's
been imported. Thanks!
-Original Message-
From: Remi Turk [mailto:[EMAIL PROTECTED]
Sent: Thu 12/29/2005 4:34 PM
To: Scherrer, Chad
Cc: S Koray Can; haskell-cafe@haskell.org
Subject: Re: [Haskell-cafe] RE:
On Thu, Dec 29, 2005 at 10:36:37PM +0100, Tomasz Zielonka wrote:
On Thu, Dec 29, 2005 at 03:34:10PM -0500, Cale Gibbard wrote:
The issue with it taking too long seems to basically be as Joel said,
only one of the threads can take that MVar at a time. Even if the time
that it's taken is
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